Most of conventional plastics are based on petroleum as the raw material thereof. In recent years, however, there is a concern regarding petroleum depletion, and CO2 generated on combustion is a cause of global warming. Thus, chemicals derived from biomass, referred to as carbon neutral, have recently attracted attention as substitutes of petroleum. Meanwhile, a methacrylic resin, which is a type of plastics, has excellent characteristics such as transparency and weather resistance and thus has been used for various applications. As a raw material of such methacrylic resin, methyl methacrylate has been used. As a method for producing methacrolein or methacrylic acid, which is a raw material of the methyl methacrylate, the following method is known. In other words, there is a catalytic gas phase oxidation method which uses tert-butanol, methyl tert-butyl ether, or isobutylene as a raw material.
Various methods for producing a raw material to be used for production of methacrylic resin have been conventionally known. Patent Literatures 1 to 4 and Non Patent Literature 1 describe methods for synthesizing isobutylene from isobutanol.